Wednesday, 24 March 2010

On Chiffchaffs...

After work late this afternoon a quick whiz around Seaton and Black Hole Marshes revealed very little - except Chiffchaffs! There has obviously been a bit of a fall of these today; there were at least ten in the Borrow Pit, three more besides the sewage works on Seaton Marshes and several calling and singing from the gorse hedge which runs along the southern edge of Black Hole Marsh.

Whilst on the subject of Chiffchaffs, I will now talk about the only bird we caught (whilst I was there anyway) at Colyford Common yesterday, a Chiffchaff. This Chiffchaff in fact...

We caught it in the net by the bird feeders!?

It was great fun ageing this bird, a look at its tail showed a nice fresh central tail feather amongst the grotty old ones...

This alone could indicate this bird is aged 5 as often the central tail feathers are moulted during the patial post juvenile moult in Chiffchaffs.

5 is ringing jargon for a bird which is definitely in its second calendar year (so a bird born last year).

BUT if any bird was to loose an odd tail feather for one reason or another, a new feather would be grown in its place. If the bird was a young-un, the new tail feather grown would look adult-like, so we need to see more....

The finger is pointing to the inner most greater coverts

I'll blow them up a bit...

Notice the nice green edged inner GCs, compared with the rest which look much greyer edged and duller

This confirms this Chiffchaff can be aged as a 5 as the two inner most GC's have been moulted and replaced by new adult GC's, whereas the remaining GC's are juvenile feathers. If this bird had completed a full adult moult then it would have replaced ALL the GC's during the birds moult last summer/autumn and they'd all look the same.

Now time for the only non-Chiffchaff part of this post.... Whilst ringing at Colyford my first Swallow of the year flew over heading south. Yes it was going in the wrong direction, but I don't blame it as it was damp, foggy and windy!! It's certainly the way I would have been travelling if I were a Swallow!

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